Plan your project capacity
Define your cameras first, then expand the professional recording, storage and network settings as needed. Results update as you change inputs.
Project information
Shared retention targets and disk-space assumptions.
This section records project identity and input sources. Advanced recording, camera optics and PoE/switch assignments can be expanded under each camera group. System-wide network, UPS, RAID/NVR, compliance and report settings appear in the panels below. Manufacturer verification and on-site tests are still required.
Camera groups
Create separate groups for cameras with different specifications.
How do I use professional camera settings?Expand only the sections you need; other settings may remain at their defaults.Open guide
- Recording mode and bitrate: Choose continuous, scheduled or event recording; specify day/night Mbps values if needed.
- Recording schedule and retention: Expand this if schedules vary by weekday or this group needs a different retention period.
- Substream and event buffer: Use when additional viewing streams or pre-/post-event recording are required.
- Expert settings: Use for scene, optical image detail and PoE calculations.
Important: Collapsing a panel does not reset enabled settings. To disable a feature, change its Disabled/Enabled selection within the panel. Your entered values are retained.
Per-group calculation breakdown
See which cameras account for the storage requirement.
| Camera group | Quantity | Camera bitrate | Daily data | 30-day recording |
|---|
View required video storage separately from the free-space target.
View the total average Mbps of camera streams.
Calculate retention days from existing usable disk capacity.
Review inputs and results independently.
How does the calculation work?
For each camera group, the Daily GB = Camera count × Mbps × Recording hours per day × 0.45 formula is used. Total video data is multiplied by the target number of days.
With a 20% free-space reserve, the usable capacity target Video TB ÷ 0.80 is obtained. Example: 16 cameras × 3 Mbps × 24 hours × 30 days = 15.552 TB of video data.
Calculation limitations
- Codec choices such as H.265 do not further reduce a manually entered bitrate.
- When using manual Mbps, motion recording, day/night variation and VBR behavior must already be reflected in the input. Automatic Mbps uses a generic, uncalibrated scene assumption and may differ from actual recordings.
- RAID is calculated separately through optional Simple disk planning or Professional mode; file-system overhead, audio and additional network traffic are considered in the professional model.
- 30 days is only an example retention target, not a universal legal retention period.
30-day recording capacity for 8, 16, 32 and 64 cameras
A camera’s average recording bitrate is 3 Mbps, daily recording time is 24 hours, target retention is 30 days and the portion of usable capacity left free is 20% are assumed. The table values are not automatically estimated from camera megapixels.
| Camera count | Total average bitrate | Daily recording | 30-day video data | Target with 20% free space |
|---|---|---|---|---|
| 8 cameras | 24 Mbps | 259.2 GB | 7.776 TB | 9.72 TB |
| 16 cameras | 48 Mbps | 518.4 GB | 15.552 TB | 19.44 TB |
| 32 cameras | 96 Mbps | 1,036.8 GB | 31.104 TB | 38.88 TB |
| 64 cameras | 192 Mbps | 2,073.6 GB | 62.208 TB | 77.76 TB |
Formula: Daily GB = camera count × average Mbps × recording hours per day × 0.45. Video TB = daily GB × days / 1,000. Target usable TB = video TB / (1 − free-space fraction).
Frequently asked questions
How many TB are required for 16 cameras recording for 30 days?
If each camera records continuously at an average of 3 Mbps, video data amounts to 15.552 TB. Allowing 20% free space requires 19.44 TB of usable capacity. RAID and file-system losses are not included in this example.
Why doesn’t selecting H.265 automatically reduce storage requirements?
Because the user already enters the average Mbps, the effect of compression is included in that bitrate. Two streams recorded at the same Mbps generate the same data volume. Codec differences are considered when estimating bitrate.
Does motion-triggered recording reduce network traffic?
Not necessarily. A camera may continuously stream to an NVR or VMS while only the disk-writing time changes. This version accounts for recording hours in video storage, but does not reduce camera network throughput by those hours.
What is the difference between TB and TiB?
TB is decimal: 1 TB = 1,000,000,000,000 bytes. TiB is binary: 1 TiB = 1,099,511,627,776 bytes. The calculator displays both.
Can I purchase an NVR and HDDs based on these results alone?
This tool supports initial capacity planning. Before a final purchase, verify the NVR’s inbound/outbound bandwidth, disk bays, supported HDD capacity, RAID configuration and camera operating conditions against manufacturer documentation.
How many TB are required for 32 cameras over 30 days?
At an average of 3 Mbps per camera with continuous recording, 32 cameras produce 31.104 TB of video data in 30 days. With a 20% free-space reserve, plan for 38.88 TB of usable capacity. Actual usage varies with bitrate and recording hours.
Does reducing daily recording hours also reduce camera network bandwidth?
Not always. Even when an NVR/VMS writes recordings only during certain hours, cameras may continue sending the same video streams over the network. This calculator applies daily recording hours to storage but does not automatically reduce total average camera Mbps.
Calculation method and technical assumptions
This tool uses manual / measured Mbps or automatic bitrate estimation with explicit assumptions for independent preliminary planning. Recording data, network traffic and physical disk capacity are different concepts and must not be used interchangeably.
- Recording capacity: Daily decimal GB is calculated as camera count × average Mbps × recording hours per day × 0.45. Retention days, free-space target and, in Professional mode, file-system/VMS assumptions are applied separately.
- Scene complexity and automatic estimation: Choosing low, medium or high scene motion changes only automatic Mbps estimation. The baseline is an assumed 3 Mbps for a 4 MP, 15 FPS, H.265 camera in a medium scene; it is not a manufacturer measurement. The 0.5×–2× range illustrates possible scenarios, not a statistical confidence interval.
- Bitrate and network: Day/night lighting, scene movement, codec, CBR/VBR settings, audio, extra streams and client count can change actual throughput. Measured bitrate is more reliable than a generic assumption.
- Storage and hardware: Raw HDD label capacity, post-RAID space, usable recording budget, NVR performance and PoE port power limit are checked separately. Final equipment selection requires product documentation and on-site testing.
The calculation method is manufacturer-independent. IEC/IEEE/ONVIF references identify technical standards and verification frameworks; this software does not automatically certify any device or project.
Related resources: NVR retention-time calculation and electronic security calculation tools.
Confidence level: Accuracy of manual Mbps depends on user settings or measurements. Automatic mode cannot guarantee exact retention for every camera, lighting condition or scene. No additional manufacturer-specific savings are assumed for H.264+/H.265+; MJPEG and custom codecs require manual measurement.
Need a technical assessment for your project?
Include the calculated camera count, storage capacity and average network traffic in your technical assessment request.